Hydraulic devices are excellent for transferring large amounts of torque into remote locations. The torque is generated by capturing a pressurized fluid within an expanding gerotor cell. The gerotor cells are defined by the contact between the teeth of a rotor and the lobes of a surrounding stator. This contact divides the pressure arc between the rotor and the stator into a series of gerotor cells.
Among the performance characteristics that are considered important in low-speed, high-torque gerotor motors are volumetric efficiency and smooth operation. When the motor, especially a hydraulic motor of the spool valve type, is operated at a low speed and a high torque, if there was a substantial amount of leakage, the motor tends to run roughly. Such inconsistency can result in rough operation of the associated piece of equipment driven by the gerotor motor.